Chilly zombie movies are perfect for summer. On May 21, director Yeon Sang-ho's zombie film Colony opened. It's the latest in the K-zombie series that includes Train to Busan, Seoul Station and Peninsula. Previously, zombies unconditionally sprinted toward sounds, but this time they communicate and learn from each other, moving like a single body ("Colony") and forming collective intelligence.
Scientists at Brazil's National Institute of Amazonian Research (INPA) confirmed that under the tropical rainforest, animals and plants alike had become a Colony that helps the reproduction of zombie fungi. It turned out that fungi, long thought to control only insects, also exist inside moss. The fungi use insects as hosts to spread offspring, but when insects are scarce, they spread to nearby moss and lie dormant.
◇Fungi found in moss far from host insects
Fungi, such as mushrooms and molds, often grow from the bodies of insects. Cordyceps is a prime example. The name comes from the idea that while it is an insect in winter, the infected fungus pierces through the body and, in summer, grows a fruiting body that spreads spores like a plant. Among them, the predatory cordyceps genus Ophiocordyceps not only feeds on insects but also manipulates their behavior. It turns them into zombies that move as if alive even after death.
On the 30th (local time), the Brazilian team published in the international journal IMS Fungus, issued by the International Mycological Association (IMA), the results of DNA analysis of moss collected in the Adolpho Ducke Forest Reserve. Ants infected with Ophiocordyceps died with their jaws clamped into moss living on the rainforest floor.
The analysis found fungal DNA not only in zombie ants infected by fungi but also in the moss the ants bit as they died. Nearby moss was the same. Fungal DNA was even found in moss living more than 10 meters away from the host ants. In other words, the entire forest was connected by zombie fungi.
Fungi manipulate host insects to spread spores—the fungal equivalent of seeds—farther. They move them to paths where ants pass or up high trees and make them clamp their jaws into moss or leaves. Then other insects passing nearby are showered with spores and become zombies in turn. Some fungi even make the dead occasionally move their wings to spread spores to other insects that come for mating.
◇Fungi living a double life, coexisting with plants
The team said the discovery broadened understanding of cordyceps fungi. It showed the possibility that zombie fungi have a dual life cycle, not only infecting insects but also living as endophytes that symbiotically inhabit plants. Literally, a two-household life. The researchers explained that the ability to coexist with plants could help fungi survive even when insect hosts are scarce. When ant traffic is thin, they lie in wait inside the moss.
João Paulo Machado de Araújo, corresponding author of the paper and a professor at the Natural History Museum at the University of Copenhagen, said, "The phenomenon of Ophiocordyceps manipulating the behavior of host ants may not arise simply from interactions between fungi and ants, but from a complex relationship that includes plants."
Until now, it was thought that zombie ants die biting moss because moss habitats are humid, making it easy for spores to spread and germinate. The researchers said this may go further—a strategy that guides ants to moss habitats where fungi already exist or are well maintained.
In 2020, a Stanford University team in the United States also discovered zombie fungi living as endophytes in plants in high-altitude regions of China. The Brazilian team went a step further, not only finding fungi in plants that turn insects into zombies but also identifying a complex network in which these fungi lead host insects to those plants.
However, it is premature to conclude that fungal DNA detected in moss means it is an endophyte in symbiosis. It is difficult to be certain whether the fungus truly lives inside moss tissues or whether spores were simply attached to the surface or internal tissues. Moss has water-storage cells, so it may trap fungal spores contained in water droplets.
References
IMA Fungus (2026), DOI: https://doi.org/10.3897/imafungus.17.196998
Fungal Ecology (2020), DOI: https://doi.org/10.1016/j.funeco.2020.100989